The present invention relates to a boarding and/or access aid.
Boarding and access aids of this type are known in many forms. They are used with vehicles for passenger carrying service, e.g., with busses and track vehicles in public local traffic and facilitate the boarding of and alighting from vehicles in that a step plate that can be moved on the particular vehicle, can also be optionally pivotably mounted and is in the form of a ramp, a linear step or the like can be extended in the area of stops. Of course, the designation of boarding and access aid also comprises its use as an alighting and exiting aid.
The step plate, consisting e.g., of aluminum and provided with an anti-slip coating, can be provided in a rear area with wheels. Alternatively, the step plate can also consist of a running board arranged at the front and of a rolling carriage coupled in an articulated manner to its rear end and comprising wheels. The wheels are supported in the side parts of a frame mounted under the vehicle bottom in such a manner that they can move back and forth. This construction has the purpose of positioning the step plate preferably before the opening of a vehicle door between a standing and waiting area for persons to be transported, e.g., a platform, and between a bottom area in the boarding area of the vehicle in order to compensate any differences in level and/or any gap between these two areas or to make it easier to pass. This also makes it easier, e.g., for people in wheelchairs and those using baby buggies to board and alight. After the end of the alighting and boarding phase and possibly after the closing of the vehicle doors the step plate is returned to its starting position.
In a known boarding and/or access aid of the initially designated species (DE 103 51 988 A1) not only the running tracks for the wheels but also the drive means required for moving the step plate back and forth are housed in the frame fastened under or in the vehicle bottom. The drive means include a motor arranged in the back area of the frame and a crank gear connected to it and to the step plate and/or to the rolling carriage and arranged in a middle area of the frame. This does result in the advantage that the step plate can be mounted together with the associated functional and drive parts and with the frame as a complete structural unit on the vehicle bottom. The structure of the drive means, which is relatively complicated and therefore associated with high production costs, and the circumstance that it is difficult when using high-performance drives to maintain the low overall height required for the structural unit are problematic.
A non-published application of the same applicant suggested providing a threaded spindle or a toothed belt instead of the crank gear (DE 10 2005 684). However, even such drive means are associated with high production costs and can only be used with low overall heights if the step plate is provided on its bottom with recesses for at least partially receiving the toothed belts or the like. However, that would be associated with a mechanical weakening of the step plate and would make additional measures necessary for meeting the usual static requirements placed on such step plates.